# CVE-2026-52989: nvmet-tcp: propagate nvmet_tcp_build_pdu_iovec() errors to its callers

> A Linux kernel NVMe-oF TCP bug allows remote attackers to cause a denial of service by triggering uninitialized memory access during PDU processing.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Jun 2026
- **Updated:** 24 Aug 2026
- **Also known as:** BELL-CVE-2026-52989, DEBIAN-CVE-2026-52989, GHSA-m4w6-2g7f-9j5p, ROOT-OS-DEBIAN-11-CVE-2026-52989, ROOT-OS-DEBIAN-12-CVE-2026-52989, ROOT-OS-UBUNTU-2204-CVE-2026-52989, ROOT-OS-UBUNTU-2404-CVE-2026-52989, UBUNTU-CVE-2026-52989

## What is CVE-2026-52989?

CVE-2026-52989 is a critical vulnerability in Linux kernel, published on 24 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

nvmet-tcp: propagate nvmet_tcp_build_pdu_iovec() errors to its callers

Currently, when nvmet_tcp_build_pdu_iovec() detects an out-of-bounds
PDU length or offset, it triggers nvmet_tcp_fatal_error(cmd->queue)
and returns early. However, because the function returns void, the
callers are entirely unaware that a fatal error has occurred and
that the cmd->recv_msg.msg_iter was left uninitialized.

Callers such as nvmet_tcp_handle_h2c_data_pdu() proceed to blindly
overwrite the queue state with queue->rcv_state = NVMET_TCP_RECV_DATA
Consequently, the socket receiving loop may attempt to read incoming
network data into the uninitialized iterator.

Fix this by shifting the error handling responsibility to the callers.

Weakness: CWE-908 (Use of Uninitialized Resource), CWE-390 (Detection of Error Condition Without Action)

## Which versions are affected by CVE-2026-52989?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-52989?

Apply the vendor's patch.

## Is CVE-2026-52989 being exploited?

There is no known exploitation of CVE-2026-52989 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-52989 and fix it if it is affected.

What it is: CVE-2026-52989 is a critical vulnerability in Linux kernel, published on 24 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-52989 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-52989/ (Markdown: https://insights.sbomify.com/CVE-2026-52989/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-52989
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-52989
- OSV: https://osv.dev/vulnerability/CVE-2026-52989

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-52989/
Summaries are generated and may contain mistakes; the official description above is the record.